1. Jeroen van Hunen The LHCb Tracking System

2. May 22, 2006 Frontier Detectors for Frontier Physics, Elba, 2006. Jeroen van Huenen 2 The LHCb Experiment LHCb at Point 8 : a lot of activity! LHCb : a B-physics experiment that is being constructed for :  Precision measurements of the CP- violation parameters  Rare B-decays The CP parameters and rare decays are sensitive to physics beyond the standard Model

3. May 22, 2006 Frontier Detectors for Frontier Physics, Elba, 2006. Jeroen van Huenen 3 The LHCb Detector

4. May 22, 2006 Frontier Detectors for Frontier Physics, Elba, 2006. Jeroen van Huenen 4 The LHCb Tracking System Tracking Detectors

5. May 22, 2006 Frontier Detectors for Frontier Physics, Elba, 2006. Jeroen van Huenen 5 LHCb Tracking VELO seeds Long track (forward) Long track (matched) T seeds Upstream track Downstream track T track VELO track T tracks  useful for RICH2 pattern recognition Long tracks  highest quality for physics (good IP & p resolution) Downstream tracks  needed for efficient K S finding (good p resolution) Upstream tracks  lower p, worse p resolution, but useful for RICH1 pattern recognition VELO tracks  useful for primary vertex reconstruction (good IP resolution)

6. May 22, 2006 Frontier Detectors for Frontier Physics, Elba, 2006. Jeroen van Huenen 6 The VErtex LOcator (VELO) VErtex LOcator ( VELO ) vacuum tank at LHCb (P8) Front end : Beetle (0.25  m CMOS) Pitch Adapter Carbon fiber substrate with laminated kapton circuit Cooling block Al foil of 300  m to separate primary (beam) and secondary vacuum

7. May 22, 2006 Frontier Detectors for Frontier Physics, Elba, 2006. Jeroen van Huenen 7 The VErtex LOcator (VELO) n + in n-bulk sensors second metal layer for signal routing 2048 micro strips per sensor 40 – 100 μm pitch 300 μm thick 21 tracking stations in total (4 half discs per station, 2  and 2R) Radiation environment: - R= 8mm : 1.3  10 14 neq/cm 2 /year - R= 42mm : 5  10 12 neq/cm 2 /year The modules need to be replaced after 3 - 4 years. R-sensor  -sensor Status: 8 ‘pre-series’ modules produced.

8. May 22, 2006 Frontier Detectors for Frontier Physics, Elba, 2006. Jeroen van Huenen 8 The Trigger Tracker TT = Station before the magnet. Used in the trigger for momentum estimate. (small field between magnet and velo) 80 half modules in production, several are fully completed and tested. - Silicon sensors : 9.4*9.6 cm 2, 500  m thick - Long modules of 14 sensors, with max 4 sensors per front-end (Beetle)  55pF - Long Kapton cables : front-end  sensors 0.12 Tm

9. May 22, 2006 Frontier Detectors for Frontier Physics, Elba, 2006. Jeroen van Huenen 9 The Outer and Inner Tracker Outer Tracker : Straw Tubes  =5mm Inner Tracker cm OT occupancy: Average = 4.5% Hottest region = 9% IT occupancy, hottest region : 2.3% Beam Pipe Inner Tracker : Silicon micro strip 198  m pitch 65cm

10. May 22, 2006 Frontier Detectors for Frontier Physics, Elba, 2006. Jeroen van Huenen 10 The Outer Tracker 3 stations (T1 – T3) with 4 layers of straws (0 o,-5 o,5 o,0 o ) each. Drift gas : Ar(0.7)/C0 2 (0.3). Drift time is 45ns for 2.5mm. The straws are 2.4 meter long Wire is W/Au.  All modules have been produced, installation at P8 in June/July this year ASDBLR OTIS GOL

11. May 22, 2006 Frontier Detectors for Frontier Physics, Elba, 2006. Jeroen van Huenen 11 The Inner Tracker 3 stations (T1 – T3) with 4 detector boxes per station. 4 Silicon layers per box, 28 modules ( with one or two sensors each) 336 modules in total : 60 built and tested Beetle (0.25  m CMOS ) front-end One of the three IT stations Alumina Pitch adapter with Au strips Silicon sensor: p in n-bulk, 198  m pitch, 420  m and 300  m thick, 7.8  11cm 2. 1mm thick Carbon sandwich (2  2 uni- directional carbon with Airex) 25  m kapton isolation Kapton hybrid

12. May 22, 2006 Frontier Detectors for Frontier Physics, Elba, 2006. Jeroen van Huenen 12 The Expected Tracking Performance

13. May 22, 2006 Frontier Detectors for Frontier Physics, Elba, 2006. Jeroen van Huenen 13 The Expected Tracking Performance Long tracks Typically 38 measurements per track Efficiency > 95% for p > 12GeV Ghost rate 12GeV For twice the event multiplicity the efficiency drops by 4% and ghost rate increases by 7%

14. May 22, 2006 Frontier Detectors for Frontier Physics, Elba, 2006. Jeroen van Huenen 14 The Expected Tracking Performance Momentum resolution IP resolution p distribution for B tracks 1/p t distribution for B tracks

15. May 22, 2006 Frontier Detectors for Frontier Physics, Elba, 2006. Jeroen van Huenen 15 The Expected Tracking Performance BsBs K +/-  +/- K+K+ K-K- DsDs PV  B-meson decay time B-meson decay time error   (fs) Typical error on  = 37 fs Average error on  = 51 fs B s mass resolution=14 MeV Decay time resolution=37 fs This excellent decay time resolution is needed to resolve the fast oscillations.

16. May 22, 2006 Frontier Detectors for Frontier Physics, Elba, 2006. Jeroen van Huenen 16 Conclusions Construction of the LHCb tracking system well advanced Vertex Locator: 8 ‘pre-series’ modules produced (need 84 half modules) Trigger Tracker: 80 half modules in production (need 128) Outer Tracker: All modules produced Inner Tracker: 100 modules produced & 60 are fully tested (need 336) Expected performance : tracking efficiency > 95% while the ghost rate remains below 7% (for p>12 GeV) B-meson decay time resolution is 37fs Looking forward to real data!